The Animal Core will provide the basic support for the maintenance of the strains necessary for this project which are not commercially available. It will not support the production of the mice used in experiments, but rather the basal level of breeding necessary for the maintenance of unique mouse strains. The applicants will maintain the diabetic mouse, NOD, as well as four GKO mice bred onto the NOD background. In addition, the investigators will maintain the class II MHC, DM and CIITA GKO mice. Finally, the applicants will maintain LCMB TCR transgenics as well as two single chain class I transgenic, LCMV gp RIP and ubiquitous expression transgenics at the core. The Animal Core is expected to be economical, eliminating the need for each investigator to maintain their own breeding colonies.